| 摘要 |
PROBLEM TO BE SOLVED: To provide an improved aqueous emulsion vinyl acetate/ethylene(VAE) polymer adhesive which is used in packaging applications and on difficultly bondable surfaces such as a polyethylene, a poly(ethylene terephthalate) or an oriented polypropylene. SOLUTION: This VAE polymer contains from approximately 55 to 80 wt.% vinyl acetate, from 15 to 45 wt.% ethylene and from 0 to 30 wt.% one or more additional ethylene unsaturated copolymerizable monomer, based on the total weight of the monomers. A cast film of the VAE emulsion polymer should have a tensile storage modulus (the test frequency of 6.28 radian/sec) within the area encompassed by the following data points, i.e. 1×10<5> and 2×10<7> dyne/cm<2> at 23 deg.C, and 1×10<3> and 2×10<6> dyne/cm<2> at 70 deg.C, preferably within the area encompassed by the following data points, i.e., 1×10<6> and 1.5×10<7> dyne/cm<2> at 23 deg.C, and 3×10<4> and 9×10<5> dyne/cm<2> at 70 deg.C.
|
